This Friday, Lockout opens, and beyond its prison-colony-in-space hook, probably the most interesting element to this sci-fi film is "Holy cow, is that Guy Pearce kickin' all that ass?" Why, yes, it is—and it's a conscious departure from the serious dramatic roles we usually see from him (Memento, L.A. Confidential). It's always kinda fun when an actor we associate with heavy-lifting thespian excellence decides to go for the paycheck and hit the weight room. So, in honor of Lockout, I decided to go back and look at some of the more memorable actor-turned-action-star transformations of the last 20 years. Some were pretty successful. Others ended up becoming Nicolas Cage.

Star: Robert Downey Jr.Before he was an action hero: There was a period when Downey Jr.'s career trajectory was much less important than his struggles with personal demons. Legal difficulties associated with his drug problems lent him the sort of tabloid notoriety that we now reserve for walking tragedies like Lindsay Lohan. But there was no question the man could act: Everything from 1987's Less Than Zero to 1993's Short Cuts to 2000's Wonder Boys proves that. But the decision to cast him as Tony Stark in Iron Man was one of those rare examples when a really oddball choice turns out to be so perfect you wonder why it ever seemed weird in the first place.Since becoming an action hero:Iron Man made him a worldwide superstar, but what's been great about his performance in those movies—as well as the Sherlock Holmes films—is that he hasn't really had to tone down his stubbornly cockeyed persona. What makes Stark and Holmes such fun is that they're a bit kooky, even though they're sure they're smarter and funnier than everyone around them. There's something incredibly Downey Jr.-esque about those characters that he can plug into better than anyone else.Action hero rating (out of 10):8. I've complained before that Downey Jr. has focused a little too much of late on blockbusters. (It's as if he wants to aggressively make up for all that time lost to drugs and courtrooms.) But ask yourself this: What one actor makes you most excited about The Avengers? OK, fine, maybe Mark Ruffalo, but, c'mon, you're going for Robert Downey Jr. I am, too.

Star: Russell CroweBefore he was an action hero: Crowe spent a decade moving between little-seen Australian dramas (Romper Stomper) and forgettable Hollywood duds (The Quick and the Dead, Virtuosity) before making a major impact in the late '90s with L.A. Confidential and The Insider. An Oscar nominee and an actor's actor, he didn't necessarily seem like the obvious choice to play Maximus in Gladiator. (And, besides, who wanted to see sword-and-sandal movies anymore?) Well, $188 million and several Oscars later (including Best Picture and Best Actor), Crowe wasn't just an actor but a box office star.Since becoming an action hero: Rather than just diving at every blockbuster thrown his way, Crowe has been pretty darn selective about what he goes after. (Maybe it helps that, when you get right down to it, Gladiator is more a period epic than it is an action flick.) So while he was great in Master and Commander and 3:10 to Yuma, it's worth noting that he's the least interesting when he's in conventional action-movie mode, which was Robin Hood.Action hero rating (out of 10):3. It's funny how people think of Crowe as some sort of blockbuster A-lister. But, when you look at his track record, what you see is a guy who takes his acting very seriously and occasionally lucks into a big hit. He could probably be a fantastic action star—he just doesn't want to be one. Put it this way: It's sorta telling that when he finally agrees to do a comic-book movie, he plays Superman's dad in Man of Steel.

Star: Liam NeesonBefore he was an action hero: Neeson's early onscreen roles included Excalibur and Krull, so it's not like he's been doing Shakespeare in the Park since birth. (And also don't forget the underrated 1990 comic-book flick Darkman.) But before 1999, he was mostly known for high-quality dramatic work like Husbands and Wives and Schindler's List. (Amusingly, when he threw on a kilt for Rob Roy, it was overshadowed by the other movie from that year featuring a dude in a kilt, Braveheart.) Nonetheless, the guy proved he could carry a blockbuster with The Phantom Menace, which, let's be perfectly clear, is a terrible, terrible movie. But he had the right amount of gravitas and the robust physicality to at least make his role memorable. You don't just believe him as an actor—you believe he could seriously mess you up if he so desired.Since becoming an action hero: Neeson continues to do good work in smaller films like Kinsey and Chloe, but those movies have been overshadowed by his action-movie onslaught of the last three years. First there was Taken, then there was The A-Team. In between, he became one of his generation's designated Dignified Thespian Who Lends Legitimacy to a Popcorn Movie actors in Batman Begins and those Clash of the Titans movies. When earlier this year he was in a movie in which he squared off against a bunch of wolves, nobody was even surprised. That's what Liam Neeson does these days, right?Action hero rating (out of 10):5. Weirdly, while I haven't liked a lot of the movies he's done, I've always liked him in them. He never winks at the audience, and he never acts like he's slumming. (Even in Wrath of the Titans, I believed every silly word coming out of his mouth.) The guy definitely has the chops—he just needs better taste.

Star: Jake GyllenhaalBefore he was an action hero: At the turn of the century, Gyllenhaal was the go-to sensitive kid you'd put in your hip indie: Donnie Darko, Lovely & Amazing, The Good Girl. And then out of the blue, he ended up in a Roland Emmerich movie. Of course, one of the central jokes of The Day After Tomorrow was that Gyllenhaal was still the sensitive, nerdy kid. (The whole movie seemed to consist of his character running away from things or freaking out.) Naturally, the movie did really well—Emmerich movies tend to do that unless they're exposing the horrible truth that Shakespeare was a fraud—but it didn't exactly cement Gyllenhaal's status as the action star for the emo set.Since becoming an action hero: Perhaps wisely, Gyllenhaal has stuck to serious dramas, having a pretty great run with Jarhead, Brokeback Mountain, and Zodiac. But still, the action-hero siren keeps luring him back to the blockbusters, which is probably the only conceivable explanation for his appearance in Prince of Persia: The Sands of Time, which, true story, Hollywood thought you'd pay money to see.Action hero rating (out of 10):1. On screen, Gyllenhaal is funny and charming. But, sorry, I have a hard time picturing him as particularly buff. (Even in Source Code, I mostly just wanted to pinch his cheeks.) And, to think, there was a moment there when he almost took over for Tobey Maguire in Spider-Man 2.

Star: Nicolas CageBefore he was an action hero: There was once a time in the mid-'90s when Nicolas Cage was among the world's most respected actors. We can laugh about it now, but, really, it's true. He'd won an Oscar for Leaving Las Vegas, and he'd established a reputation for being a go-for-broke dramatic actor in films as different as Wild at Heart and Raising Arizona. He was unpredictable and electrifying ... which didn't make his decision to be in The Rock seem all that crazy. The guy was a bit of an oddball, so if he wanted to make a Bruckheimer film, hell, at least it would be fun. And it was, and so was the following year's Face/Off. But Con Air started making people worry: Wait, is this all he's going to do now? And the answer was: Yup, pretty much. And things just got worse from there.Since becoming an action hero:We've already told you what's become of the poor man in recent years. It never ceases to depress me. It would be one thing if he were extraordinarily successful and making bad movies—then he'd be Michael Bay, which, all things considered, isn't the worst thing in the world. No, what's worse is being Nicolas Cage in 2012: a laughing stock desperate for any paying gig he can get his hands on. Even a project that's supposed to be a can't-miss hit, like Ghost Rider: Spirit of Vengeance, crashes and burns. Sure, he can poke fun of his image on Saturday Night Live, and we can all enjoy the memory of what he used to be. But we all know the truth.Action hero rating (out of 10):-4. Are we done? I don't want to think about this poor guy any more.